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(11) | EP 0 761 149 A1 |
| (12) | EUROPEAN PATENT APPLICATION |
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| (54) | A device for brewing coffee, tea or similar drinks |
| (57) A device for brewing coffee, tea and the like. A rotor with three circumferentially
spaced cells (5,II,III) is mounted for a stepwise rotary movement within a cylindrical
housing (1) to move each of the cells successively to each of three circumferentially
spread locations, where an ingredient's inlet, a filter and a discharge opening for
dregs respectively are provided. A source of pressurized air is provided at a location
within a transitional area between the ingredient's inlet location and the filter
location so as to be active as an agitation means in the filling and extracting phase
and as a means for expelling the extract in the filter phase. |
[0003] With these well-known devices the expelling of the coffee extract is effected by means of the liquid component (hot water) that it supplied from the center of the rotor into the cell at the filtering location and pressed through the dry component(s) and the filter outwardly. Thus the supply of the liquid component (hot water) and the start of the extracting process are postponed until the filtering stage, wherein the extracting step is taking place while the water is pressed through the dry component (coffee powder).
[0004] It is an object of the invention to improve the well-known device above referred to, such that the extracting process is intensified without prolonging the time required for the preparation and deliverance of one drink unit.
[0005] Accordingly the invention provides a device of the type above referred to, that has the features as defined in the second part of claim 1.
[0006] With a device thus formed the extraction process starts at the filling location, where the respective cell is filled with all of the required ingredients (i.e. including the liquid ingredient). Moreover the extraction process is enhanced at least during a part of the rotary step towards the filtering position due to air under pressure being passed through the ingredients' mixture while still in connection with the ingredients' inlet. As soon as the cell just filled with ingredients has become disconnected from the ingredients' inlet the air under pressure becomes effective as a means for expelling the extract at the filtering location.
[0007] It is to be remarked, that it is known per se to expel coffee extract, in a coffee machine, through a filter by producing an underpressure in a discharge space under the filter (see NL-A-8500925). Furthermore it is known from NL-A-8901968 to pass pressurized air, in a coffee machine, from a space under a filter and via said filter through the coffee extract as a means for agitating the extract during the extracting process. It is not taught in this documents, however, to use the same pressurized air to expel the extract through the filter outwardly.
[0008] The invention will be hereinafter further explained by way of example with reference to the diagrammatic drawings.
Fig. 1 is a side view of the device according to the invention;
fig. 2 is a cross-sectional view through the device of fig. 1 and
fig. 3A-3E show five successive phases passed through by the device for preparing a plurality of drink units, for example cups of coffee.
[0009] The device shown in fig. 1 and 2 of the drawings comprises a substantially cylindrical, horizontally positioned container or housing 1 having at the upper side a metering hopper 2 for (hot) water and material to be extracted (for example coffee powder, tea and the like) and having at the lower side a filter 3 with a collecting trough 4 and a discharge conduit 5. The ends of the housing 1 are closed by end walls 6. A discharge opening 7 for dregs is provided laterally in the cylindrical circumferential wall, said opening extending along the entire axial length of the housing and covering an arc length of about 90° in the circumferential direction.
[0010] Three partitions 9, 10 and 11 are provided within the housing and extend from the axis of the housing radially outwardly in angular positions that are mutually spaced through 120°. The assembly of partitions 9, 10 and 11 is mounted for rotation in the housing 1; in the example shown it is rotatably supported with axle stubs 8 in the end walls 6. The radially outer longitudinal edges and the radially directed edges at the axial ends of the partitions are sealingly engaging the inner surface of the cylindrical circumferential wall and the inner side of the end walls 6 respectively.
[0011] Alternatively the partitions 9-11 may, together with the end walls 6, form a rotor that is journalled in an open ended housing 1. Such a rotor could be easily removed from the housing in the axial direction so as to facilitate cleaning of the device.
[0012] The partitions 9-11 divide the space within the housing 1 into a number of circumferentially spaced cells I, II and III. 12 designates a scraper blade that is pivotally mounted about a horizontal axis 13 and extends through the opening 7 into the cell that is located on the left side of the housing 1, with the scraper edge 14 of the scraper blade engaging the lower partition 11.
[0013] 15 designates an air supply conduit, which is connected to an air pump 16 and discharges into the circumferential wall of the housing 1 on the right side (fig. 2) at about axis level. The metering hopper 2, the filter 3 and the discharge opening 7 for dregs constitute three stations which are spread circumferentially of the housing 1. The discharge opening of the air supply conduit 15 is located in the transitional area between the "metering station" and the "filtering station".
[0014] The assembly of partitions 9-11 is rotated stepwise in the arrow direction a, e.g. by means of a time controlled stepping motor (not shown), whereby the cells I, II and III are successively moved to each of the said stations and kept stationary for a while at each of these stations.
[0015] The working of the device will be hereinafter explained with reference to fig. 3A-3E and taking as an example the preparation of two cups of coffee.
[0016] Fig. 3A shows the partition assembly 9-11 in a position, in which cell I is connected with both the metering hopper 2 and the air supply conduit 15. While in this position, the device is put into operation, e.g. by depressing a (selector) button for two cups of coffee. The depression of such a button causes a time control circuit to be energized for an immediate activation of the metering devices for (hot) water and coffee powder (not shown), so that cell I is filled through the metering hopper 2 with the ingredients required for the first cup of coffee. Simultaneously or a few seconds later the air pump 16 is put into operation for the supply of air so as to agitate the (hot) water/coffee powder mixture and thereby promote the extracting process in cell I.
[0017] Thus fig. 3A shows the device at the time at which the ingredients are supplied in the arrow directions a and b respectively to cell I. At the end of the required extracting time, which may be 6-10 seconds, energization of the stepping motor (not shown) is taking place, which causes the partition assembly 9-11 to be turned to the position shown in fig. 3B. In this position the cell I has become connected with the filter 3, while the connection with the air supply conduit 15 is maintained for a short while. This causes the extract produced in cell I to be expelled (arrow c), while simultaneously the ingredients required for the second cup of coffee are supplied to cell II (arrow d).
[0018] Well within the required extracting time for the mixture in cell II - after the extract has been expelled from cell I and delivered at the desired place under the pressure of the expelling air - the partition assembly 9-11 is turned through a small angle into the position shown in fig. 3C, in which cell II has become connected with the air supply conduit 15 and air is introduced into cell II and passed through the mixture for agitation of the latter. At that time cell II is in the same position as cell I initially in fig. 3A.
[0019] As soon as the total extracting time for the mixture in cell II has elapsed, the partition assembly 9-11 is turned from the position of fig. 3C to that of fig. 3D. During this rotary movement the dregs collected on the filter 3 in the positions of fig. 3B and 3C are pushed by the partition 9 towards the discharge opening (arrow f). This rotary movement also brings cell II and the extract therein in connection with the filter 3, while the connection between cell II and the air supply conduit is maintained, which causes the extract to be expelled through the filter under increased pressure (arrow g). Thereupon the assembly of partitions 9-11 is turned into the position shown in fig. 3E, in which the dregs collected on the filter 3 in the position of fig. 3D are pushed by the partition 11 towards the opening 7 for discharge (arrow h). This has brought the assembly of partitions 9-11 back in the initial position of fig. 3A, whereas the device has fulfilled the order of brewing two cups of coffee.
[0020] It will be understood that in the position of fig. 3C cell III could be filled with ingredients for a third cup of coffee etc. This means that two cups of coffee have been prepared within one cycle, while within the same cycle the preparation of a third cup of coffee may start already.
[0021] It is still to be remarked that when changing from the position of fig. 3D to that of fig. 3E dregs collected when changing from the position of fig. 3C to that of fig. 3D and keeping sticking to the front side of the partition 9, will be pushed outwardly through the discharge opening 7 by the scraper blade 12 that moves with its scraping edge 14 from the center outwardly across the partition 9. The scraper blade 12 is thereby moving from the position shown in full lines in fig. 2 into the position indicated by dash lines.
[0022] It will be understood that the scraper blade after the clean scraped partition has passed in the direction of rotation, will fall back into its position shown in full lines but now with its operative scraping edge engaging the front side of the next partition, as seen in the direction of rotation.
[0024] A design on the basis of a vertically positioned container could also be realized. A lying position of the container, however, is to be preferred. To enlarge the capacity of a drinks machine equipped with the device according to the invention, two or more of such devices, if desired with use of selectively operable couplings, could be placed side by side and connected.
1. A device for brewing coffee, tea or similar drinks, of the type comprising a substantially
cylindrical container, an inlet for ingredients, a filter and an opening for discharging
dregs collecting on said filter being provided at three circumferentially spaced locations
of the wall of said container, and a rotor with three circumferentially spread cells
being provided within said container for a stepwise movement to each of the three
circumferential spread locations, means being provided for expelling extract through
said filter outwardly, characterized in that the ingredients supply is adapted to
supply both the dry and liquid ingredients for the drink to be prepared and that the
means for expelling of the extract are constituted by a source of pressurized gas,
a supply conduit from said source opening into the container wall at that side, along
which the stepwise movement of the rotor is directed from the ingredients supply towards
the filter, and at a location within a transitional area between a filling position,
in which the ingredients are supplied, and a filtering position, in which the filtering
of the extract is taking place.
2. A device according to claim 1, characterized in that the said three circumferentially
spaced cells are mutually separated by axially and radially directed plate-like partitions.
3. A device according to claim 2, characterized by a scraper blade that extends obliquely
from above through the dregs discharge opening into a cell between two partitions,
the operative scraper edge of said blade engaging the forward face (i.e. the face
directing in the direction of rotation of the partition assembly) of the lower one
of the two partitions, said scraper blade being movably mounted in such a way that
with a rotary movement of the partition assembly it is caused by the lower partition
to swing, while sliding on said forward face, outwardly.
4. A device according to claim 3, characterized in that the scraper blade is swingably
suspended at its end turned away from the operative scraper edge.
5. A device according to claim 4, characterized in that the scraper blade extends, from
a swinging axis positioned adjacent the vertical midplane and above the container
space, at first outwardly in a substantial horizontal direction and then obliquely
downwardly and inwardly.